This invention relates to a cylinder injecting fuel injection valve and, particularly, to a cylinder injecting fuel injection valve provided with a hermetic seal.
Examples of conventional cylinder injecting fuel injection valve are found in Japanese Patent Laid-Open No. 9-126089, Japanese Patent Publication No. 2768522 and Japanese Patent Laid-Open No. 10-89192. In the cylinder injecting fuel injection valves disclosed in these patent documents, high-pressure seals are required for maintaining hermetic seals between the cylinder and the fuel injection valve.
However, the above-described high pressure seals for realizing the seal of the combustion gas aims only at the sealing function, so that the blocking of 47, the heat from the combustion gas is not satisfactory because the heat insulation was not positively provided but was only resulted from the gas sealing. On the other hand, components designed for heat insulation or heat dissipation from the injection valve to the cylinder head pauses problems in easy assembly, sprayed fuel and costs.
In the example disclosed in Japanese Patent Laid-Open No. 9-126089, the main object is to dissipate the heat of the injection valve tip from the combustion gas is relieved through the metallic ring into the cylinder head, so that, as long as the ring has a notch, it has been difficult to obtain a combustion gas seal although the ingress of flames into the clearance may be prevented. Even when two rings are used together in a juxtaposed relationship, a high-pressure combustion gas as high as 7 to 8 MPa has not been satisfactorily sealed.
The example disclosed in Japanese Patent Publication No. 2768522 is a fuel injection valve for a Diesel engine in which a massive tightening torque is needed to tighten the tightening nut between the injection valve and the cylinder head. While the seal for the combustion gas between the cylinder head and the tightening nut is provided by a ring packing in this case, the seal for the combustion gas between the injection valve and the tightening nut in the case of Diesel fuel injection valve is known to be achieved by a ring-shaped packing at the upstream of the heat insulating plate. Such the heat insulating plate becomes supported only when the fuel injection valve and the tightening nut are combined together and it is not engaged with the injection valve by itself.
In the example disclosed in Japanese Patent Laid-Open No. 10-89192, while the discussion is made as to the sealing of the fuel injection valve against the combustion gas as well as the improvements in dissipation of the heat from the fuel injection valve heated by the combustion gas, the sealing of the combustion gas is achieved by the gasket 13.
Also, in the arrangements disclosed in Japanese Patent Laid-Open Nos. 9-126089 and 10-89192, it is necessary to eliminate the clearance defined between the fuel injection valve and the cylinder head, so that the fuel injection valve is difficult to be mounted or dismounted. Also, it is possible that a damage may be given to the inner surface of the cylinder head and the outer surface of the fuel injection valve by attaching the heat dissipating device thereto, so that they can not possibly serve as desired after the fuel injection valve is detached and attached for any reasons even when a fresh heat dissipation device is substituted.
Further, since there is no clearance in the radial direction, if the fuel injection valve and the cylinder head are assembled together with a poor alignment, the components around the nozzle of the fuel injection valve and the components in the vicinity of the electromagnetic drive unit of the injection valve are subjected to relative lateral loads, resulting in the possibility of changing the performance of the fuel injection valve itself.
According to Japanese Patent Laid-Open No. 9-112697 assigned to the same assignee of the present application, the inner diameter side of the seal ring is provided with engagement projections for engaging with the fuel injection valve to facilitate the assembly into the fuel injection valve. However, due to the axially asymmetrically provided projections in this seal ring, the stress distribution in the seal ring during the usage is not axial symmetry, leading to decrease in the durability. Also, the copper gasket 32 disclosed in Japanese Patent Laid-Open No. 9-112382 does not serve to seal the combustion gas but only serves to provide an intimate contact between the flange of the fuel injection valve and the cylinder head because this arrangement cannot provide a pressure load sufficiently large to press and seal the combustion gas.
If a complicated structure is used at the nozzle tip portion of the fuel injection valve as a counter measure for deposit on the fuel injection valve, the productivity and the cost are adversely affected.
According to Japanese Patent Laid-Open No. 10-252609, a copper gasket having a heat conductivity equal to or higher than the injector is disposed within the axial clearance between the injector and the cylinder head. This gasket is required not only to conduct the heat but also to seal the combustion gas. When the copper gasket is plastically deformed in order to seal the combustion gas, a significantly large pressure load must be applied to the copper gasket, which may cause the deformation of the precision-machined portion within the injector and the change in its performance. Also, another example disclosed in this same patent document is, similarly to that disclosed in Japanese Patent Laid-Open No. 10-89192, required to have no clearance between the fuel injection valve and the cylinder head, posing a problem of difficult attaching and detaching operation of the fuel injection valve.
Accordingly, the main object of the present invention is to provide a cylinder injecting fuel injection valve free from the above-discussed problems of the conventional cylinder injecting fuel injection valve.
Another object of the present invention is to provide a cylinder injecting fuel injection valve that is reliable, and that is excellent in heat insulation with a simple structure, being good in insulation of heat of the combustion gas or in heat dissipation from the fuel injection valve to the cylinder head on one hand, and that is satisfactory in sealing function, realizing the improvements in the insulation of the fuel injection valve from the combustion gas and in the dissipation of the heat of the fuel injection valve heated by the combustion gas.
With the above objects in view, the present invention resides in a cylinder injecting fuel injection valve that can be inserted into a cylinder head of an internal combustion engine and supported by a shoulder portion of a fuel injection valve main body and a shoulder portion of the cylinder head. The fuel injection valve includes a valve seat facing to a combustion chamber when attached to the engine and a swirler member providing whirling movement to the injected fuel. The valve has a seal gasket sealing, when attached to the engine, at least first two of three regions defined between the shoulder portion of the fuel injection valve main body, the shoulder portion of the cylinder head and an outer circumferential portion of the fuel injection valve main body. The gasket comprises an annular metallic elastic member brought into contact with the shoulder portion of the fuel injection valve main body, the shoulder portion of the cylinder head and the outer circumferential portion of the fuel injection valve main body, and an annular support member elastically supporting the metallic elastic member and brought into elastic contact with the shoulder portion of the cylinder head and the shoulder portion of the fuel injection valve main body. The gasket abuts at an abutting surface against the shoulder portion of the cylinder head at an axial position closer to the combustion chamber of the internal combustion engine than an upstream side end surface of the swirler member.
The present invention also resides in the cylinder injecting fuel injection valve that can be inserted into a cylinder head of an internal combustion engine and supported by a shoulder portion of a fuel injection valve main body and a shoulder portion of the cylinder head. The fuel injection valve includes a valve seat facing with a combustion chamber when attached to the engine and a swirler member providing whirling movement to injected fuel. The valve has a seal gasket surrounding, when attached to the engine, the fuel injection valve main body and sealing at least first two of three regions defined between the shoulder portion of the fuel injection valve main body, the shoulder portion of the cylinder head and an outer circumferential portion of the fuel injection valve main body. The gasket comprises an annular metallic elastic member brought into contact with the shoulder portion of the fuel injection valve main body, the shoulder portion of the cylinder head and the outer circumferential portion of the fuel injection valve main body, and an annular support member elastically supporting the metallic elastic member and brought into elastic contact with the shoulder portion of the cylinder head and the shoulder portion of the fuel injection valve main body. The metallic elastic member of the gasket has a contacting surface contacting with an outer circumferential portion of the fuel injection valve main body, the end portion of the contacting surface of the metallic member being positioned at an axial position closer to the combustion chamber of the internal combustion engine than an upstream side end surface of the swirler member.
Also, the present invention resides in the cylinder injecting fuel injection valve that can be inserted into a cylinder head of an internal combustion engine and supported by a shoulder portion of a fuel injection valve main body and a shoulder portion of the cylinder head. The fuel injection valve includes a valve seat facing with a combustion chamber when attached to the engine and a swirler member providing whirling movement to injected fuel. The valve has a seal gasket surrounding, when attached to the engine, the fuel injection valve main body and sealing at least first two of three regions defined between the shoulder portion of the fuel injection valve main body, the shoulder portion of the cylinder head and an outer circumferential portion of the fuel injection valve main body. The gasket comprises an annular metallic elastic member brought into contact with the shoulder portion of the fuel injection valve main body, the shoulder portion of the cylinder head and the outer circumferential portion of the fuel injection valve main body, and an annular support member elastically supporting the metallic elastic member and brought into elastic contact with the shoulder portion of the cylinder head and the shoulder portion of the fuel injection valve main body. The gasket may have an inner circumferential surface opposing to an outer circumferential surface of at least the swirler body of the swirler body and the valve seat heated by the combustion chamber.
The metallic elastic member of the gasket may be made of a spring steel such as stainless steel and the support member may be made of compound material of non-asbestos material.
The metallic elastic member of the gasket may have a surface coating of a fluororesin or fluororubber.
The support member of the gasket may be an annular member and the metallic elastic member may be an annular member having a U-shaped cross-sectional configuration disposed on a surface of support member.
The gasket may comprise a plurality of gasket elements stacked in an axial direction.